I simply added a text warning to mrbug's v2 design so people/guests/roommates know to be careful with the disposal box.

I only put text on the front so it would still be stackable.

There is a large text and small text version, depending on how much of a warning you want to give. I prefer the larger text one.

Shoot me a message if you want the .blend files (if anyone wants to try for dualstrution or something).

Print it out. Carefully insert razor blades when needed. Dispose with something covering the opening. Stay safe.